/*
 * Copyright � 2002-2011 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

using System.Reflection;
using System.Web;
using System.Web.Script.Services;
using Spring.Context;
using Spring.Util;
using Spring.Web.Services;
using Spring.Web.Support;

namespace Spring.Web.Script.Services;

/// <summary>
/// An <see cref="System.Web.IHttpHandlerFactory"/> implementation that
/// creates a handler object for either ASP.NET AJAX 1.0 or Spring web services.
/// </summary>
/// <author>Bruno Baia</author>
/// <author>Thomas Broyer</author>
public class ScriptHandlerFactory : AbstractHandlerFactory, IHttpHandlerFactory
{
    private static readonly Type scriptHandlerFactoryType =
        typeof(ScriptServiceAttribute).Assembly.GetType("System.Web.Script.Services.ScriptHandlerFactory");

    private static readonly FieldInfo scriptHandlerFactory_webServiceHandlerFactory =
        scriptHandlerFactoryType.GetField("_webServiceHandlerFactory", BindingFlags.NonPublic | BindingFlags.Instance);

    private static readonly Type webServiceDataType =
        typeof(ScriptServiceAttribute).Assembly.GetType("System.Web.Script.Services.WebServiceData");

    private static readonly ConstructorInfo webServiceData_ctor =
        webServiceDataType.GetConstructor(BindingFlags.NonPublic | BindingFlags.Instance, null, new Type[] { typeof(Type), typeof(bool) }, null);

    private static readonly MethodInfo webServiceData_GetCacheKey =
        webServiceDataType.GetMethod("GetCacheKey", BindingFlags.NonPublic | BindingFlags.Static, null, new Type[] { typeof(string) }, null);

    private readonly IHttpHandlerFactory scriptHandlerFactory =
        (IHttpHandlerFactory) Activator.CreateInstance(scriptHandlerFactoryType, true);

    /// <summary>
    /// Creates a new instance of the <see cref="ScriptHandlerFactory"/> class.
    /// </summary>
    public ScriptHandlerFactory()
        : base()
    {
        scriptHandlerFactory_webServiceHandlerFactory.SetValue(
            this.scriptHandlerFactory,
            new WebServiceHandlerFactory());
    }

    /// <summary>
    /// Retrieves an instance of the <see cref="System.Web.IHttpHandler"/>
    /// implementation for handling web service requests
    /// for both Spring and ASP.NET AJAX 1.0 web services.
    /// </summary>
    /// <param name="context">The current HTTP context.</param>
    /// <param name="requestType">The type of HTTP request (GET or POST).</param>
    /// <param name="url">The url of the web service.</param>
    /// <param name="pathTranslated">The physical application path for the web service.</param>
    /// <returns>The web service handler object.</returns>
    public override IHttpHandler GetHandler(HttpContext context, string requestType, string url, string pathTranslated)
    {
        string filename = VirtualPathUtility.ToAbsolute(context.Request.FilePath);
        string cacheKey = (string) webServiceData_GetCacheKey.Invoke(null, new object[] { filename });
        object webServiceData = context.Cache.Get(cacheKey);
        if (webServiceData == null)
        {
            IConfigurableApplicationContext appContext = base.GetCheckedApplicationContext(url);
            string appRelativeVirtualPath = WebUtils.GetAppRelativePath(url);
            NamedObjectDefinition nod = FindWebObjectDefinition(appRelativeVirtualPath, appContext.ObjectFactory);

            if (nod != null)
            {
                Type serviceType = null;
                if (appContext.IsTypeMatch(nod.Name, typeof(WebServiceExporter)))
                {
                    WebServiceExporter wse = (WebServiceExporter) appContext.GetObject(nod.Name);
                    serviceType = wse.GetExportedType();
                }
                else
                {
                    serviceType = appContext.GetType(nod.Name);
                }

                object[] attrs = serviceType.GetCustomAttributes(typeof(ScriptServiceAttribute), false);
                if (attrs.Length > 0)
                {
                    webServiceData = webServiceData_ctor.Invoke(new object[] { serviceType, false });
                    context.Cache.Insert(cacheKey, webServiceData);
                }
            }
        }

        return this.scriptHandlerFactory.GetHandler(context, requestType, url, pathTranslated);
    }

    /// <summary>
    /// Enables a factory to reuse an existing handler instance.
    /// </summary>
    /// <param name="handler">The <see cref="System.Web.IHttpHandler" /> object to reuse.</param>
    public override void ReleaseHandler(IHttpHandler handler)
    {
        this.scriptHandlerFactory.ReleaseHandler(handler);
    }

    /// <summary>
    /// Create a handler instance for the given URL.
    /// </summary>
    /// <param name="appContext">the application context corresponding to the current request</param>
    /// <param name="context">The <see cref="HttpContext"/> instance for this request.</param>
    /// <param name="requestType">The HTTP data transfer method (GET, POST, ...)</param>
    /// <param name="rawUrl">The requested <see cref="HttpRequest.RawUrl"/>.</param>
    /// <param name="physicalPath">The physical path of the requested resource.</param>
    /// <returns>A handler instance for the current request.</returns>
    protected override IHttpHandler CreateHandlerInstance(IConfigurableApplicationContext appContext, HttpContext context, string requestType, string rawUrl, string physicalPath)
    {
        throw new NotSupportedException();
    }
}